To provide high levels of reliability and availability, it is common to provide spare or redundant computational components. FIG. 6 depicts a conventional main and spare processor architecture in a distributed telecommunications network. Telecommunications switch or server 600 comprises main processor 604 and duplicated processor 608. Duplicated processor 608 can provide the same services as main processor 604 in the event that the main processor 604 malfunctions. To provide additional tiers of redundancy, a plurality of spare processors 612a-n are provided at different locations in the network. The various layers of redundancy provide fault tolerance and high availability, which is particularly important in telephony applications. When a spare processor detects that the primary and duplicated processors are no longer in control of the network (due for example to a failure of the main/duplicated processor or a loss of network connectivity to the server/switch 600), the spare processor assumes control for its assigned portion of the network. The spare processor typically is configured to run the same software and therefore provide the same functionality as the main and duplicated processors. As a result the customer is able to maintain the functionality of its telecommunications system via the spare processor when the main processor is not available.
In telecommunication applications, spare processors can be configured in many different ways. In one configuration, the spare processors 612a-n are referred as Survivable Remote Processors or SRPs, and each serves a corresponding port network (not shown). If the corresponding connection 616a-n to the switch/server 600 goes down (causing a loss of network connectivity) and/or if the main and duplicated processors fail (and the link to the corresponding port network or the expansion interface comes up), each of the survivable remote processors 612a-n is activated and serves its corresponding port network. In another configuration, the spare processors 612a-n are referred to as Local Spare Processors or LSPs, and each serves a corresponding packet-switched media gateway (not shown). If the LSP is contacted by a network node, such as a telephone or media gateway processor, that is preinstructed to use or register with the LSP in the event of malfunctions of the main and duplicated processors, the LSP is activated and serves the network nodes contained in its preassigned network region. In yet another configuration, the spare processors 612a-n are referred to as Wide Area Network Spare Processors or WSPs, and each WSP is configured to operate the entire network and not just a portion of the network as in the case of the SRP and LSP. To avoid conflicts, the WSPs are arranged in a hierarchy such that each WSP is only activated in the event that the main and duplicated processor and the WSP(s) higher in the hierarchy (if any) are not operational. A WSP periodically polls the main and/or duplicated processors and WSP(s) higher in the hierarchy and, if a response is not received within a configurable time period, the WSP concludes that the corresponding polled processor is not operational.
The use of SRPs, LSPs, and/or WSPs can cause difficulties in providing right-to-use protection and software copy protection. Typically, spare processors are sold at a significant discount relative to main processors. The rationale is that the software on the spare processor is used less and should therefore cost less than the main processor's software. This presents an opportunity for customers to deprive the software supplier of revenue by buying the spare processor software and using it as the main processor software.
Existing licensing approaches do not address this problem. In one telecommunications licensing approach for example, a valid license file is required to run a computational component. This approach is discussed in detail in copending U.S. patent application entitled “Securing Feature Activation in a Telecommunication System”, Ser. No. 09/357,679, filed Jul. 20, 1999, to Serkowski, which is incorporated herein by this reference. In such licensing verification systems, the license file contains a serial number that must be present on the processor that is to execute the licensed software for the license to be valid and the software to be executable. In telecommunication applications, the serial number of the main processor 604 must be in the license file for the processor 604 to run the licensed software.
The license file also contains a software name and/or version of the licensed telecommunication application and licensed features. The data structures corresponding to the features are of two types. In a type 1 feature, the data structures reflected enablement or disablement of the corresponding feature using a simple on/off state. Examples of features falling into this category include abbreviated dialing enhanced list, audible message waiting, vectoring, answer supervision by call classifier, ATM trunking, agent states, dial by name, DCS call coverage, echo cancellation, multifrequency signaling, and wideband switching. In a type 2 feature, the data structures include a single numeric value and/or a name kind of entry. Examples of features falling into this category include logged-in agents, offer category, maximum numbers of concurrently registered IP stations, administered IP trunks, ports, and concurrently administered remote office stations/trunks, and call center release.
This licensing scheme is not configured for licensing spare processors such that they cannot be permanently used as main processors. To provide the desired reliability and availability of redundant systems, not only the main but also the spare processors must be able to be enabled by the licensing verification system. However, if a license is provided for a spare processor, there is nothing to prevent the spare processor from being used as a main processor on a permanent basis.